A. Field of the Invention
This invention is in the field of heat exchangers used to transfer heat from one fluid to another, and particularly heat exchangers to transfer heat to one fluid flowing through a shell from a second fluid flowing through tubes extending through such a shell.
B. Background of the Invention
Fluid heat exchangers are widely used in the industry, one common heat exchanger comprising a cylindrical housing or shell encompassing a bundle of tubes, wherein heat from a first fluid flowing through the tubes is transferred to a second fluid flowing through the housing, as a result of the second fluid flowing in contact with the outer surfaces of said tubes. The second fluid enters the shell through a nozzle and is directed initially to an impingement plate which deflects and redirects the second fluid to flow toward and about the outer surfaces of said tubes, as generally disclosed in U.S. Pat. No. 3,938,588
The inlet fluid initially has a high velocity and dynamic force when it impacts on the impingement plate. In many conventional shell and tube type heat exchangers the impingement plate adjacent the inlet nozzle protects the tubes from direct impact of the high velocity inlet fluid, but often creates operational problems when fluid flowing downstream of the impingement plate has reduced velocity due to the vortex effect of fluid motion at the sides of the impingement plate. This results in fouling accumulation on surfaces of the tubes, particularly in the region designated herein as “fouling area” immediately below the conventional impingement plate. Such fouling retards heat transfer to tubes in that area and furthermore may create a corrosive environment on the outer surfaces of said tubes. The present invention provides a new and very different impingement plate device to reduce fouling accumulation, to enhance heat transfer and to reduce corrosion.